First, I played around with watercolors, using lots of different techniques.
Second, I realized the mistake in my previous thinking. I posted last week that I wanted to "retro-fit a background" onto my sketch. It occurred to me that retro-fitting is a recipe for disaster. I must not think of how to back up, if you will; I must think of a way to go forward if I want to make an organic whole.
So, this is the sketch as is: